Remove some more title-casing from headlines.

content/docs/practices/naming.md

@@ -10,7 +10,7 @@ for using Prometheus, but can serve as both a style-guide and collection of
 best practices. Individual organizations might want to approach e.g. naming
 conventions differently.
 
-## Metric Names
+## Metric names
 
 A metric name:
 

content/docs/querying/operators.md

@@ -5,7 +5,7 @@ sort_rank: 2
 
 # Operators
 
-## Arithmetic Binary Operators
+## Arithmetic binary operators
 The following binary arithmetic operators exist in Prometheus:
 
 * `+` (addition)
@@ -31,7 +31,7 @@ Vector elements that don't find an exact label match on the other side get
 dropped from the result. The metric name of the result vector is carried over
 from the left hand side of the expression.
 
-## Comparison / Filter Binary Operators
+## Comparison / filter binary operators
 
 The following binary comparison/filter operators exist in Prometheus:
 
@@ -57,7 +57,7 @@ find an exact label match on the other side of the expression get dropped from
 the result, while the others get carried over into a result vector with their
 original (left-hand-side) metric names and data values.
 
-# Logical/Set Binary Operators
+# Logical/set binary operators
 
 These logical/set binary operators are only defined between instant vectors:
 
@@ -74,7 +74,7 @@ over from the left-hand-side vector.
 which don't have matching labelsets in `vector1`. The metric name is carried
 over from the left-hand-side vector in both cases.
 
-# Aggregation Operators
+# Aggregation operators
 
 Prometheus supports the following built-in aggregation operators that can be
 used to aggregate the elements of a single instant vector, resulting in a new